That means they're going to be the most expensive routers you find. If you have a high speed connection and are okay spending extra, it could be worth the upgrade. Most new gadgets should be compatible with it in the near future.
Both 802.11ac and 802.11n routers are backward-compatible with older standards such as 802.11g and 802.11b, so older wireless gadgets will still work.
All routers have several ports. There's the Wide Area Network port to connect your Internet modem. Then there are the Local Area Network ports for connecting wired gadgets, such as desktop computers.
Most routers will have four LAN ports, which is enough for a standard home network. However, some come with fewer LAN ports. Make sure you get a router that has enough for your needs.
The most critical part of any router is wireless security. You don't want to leave your network open to criminals and nosy neighbors, after all. Make sure the router supports WPA2 encryption.